1. Technical Field of the Invention
The present invention relates to a seat guide for mounting a car seat and for its positional adjustment in the direction of an axis of displacement, with two guide rails installed parallel to the axis of displacement, and with support rollers which, by rolling, cooperate with and move relative to the guide rails to support the vertical load.
2. Discussion
These kinds of seat guides have a special problem, in that large dimensional tolerances appear because of the large number of sheet metal parts used to manufacture the body, so that the clearance of the seat""s guide components, measured in the direction of a vehicle""s horizontal lateral axis (Y-axis), can even differ in the range of several millimeters. Furthermore, dimensional tolerances in the manufacture of the seat frame cannot be neglected. All of these tolerances have to be compensated so that the seat guide operates without trouble, i.e. to guarantee above all that there is no jamming when the position is adjusted. This problem is particularly important for bench seats above all, because their large width (span between the lateral guides) also makes them susceptible to rocking motion around a vertical axis (Z-axis), which can result in wedging of the bench seat.
A seat guide of the generic type is known from DE19547034A1. Here, two double-conical rollers (guide rolls) run on each of two guide rails and are guided axially movable in movable bearing arrangements on at least one side to compensate tolerances. This seat guide is basically very functional, but practice has shown that this design can only be realized at relatively high cost, because the bearings have to withstand certain forces, which can be quite high in a collision, above all. Special materials must therefore be used for the bearings. It has furthermore been shown, that no absolutely jam-free adjustment of the bench seat can be achieved in the longitudinal direction, even with this known design.
DE4330133A1 describes another rail guide for car seats, which is moreover designed as a slip-in guide with plastic slide blocks guided slidable in the guide rails. To compensate tolerances, support pieces are installed on the seat, which first of all have a bearing arrangement that can pivot around their longitudinal axis, and which secondly can slide in the direction of their longitudinal axis on at least one side of the seat. Externally, these support pieces feature plastic slide blocks, which slide in the longitudinal guide rails.
DE3920077A1 similarly deals with a car seat guided in rails, whereby the seat is guided on slide supports in the rails. Here, a fastening device, which is also supposed to compensate lateral play in the rails caused by structural tolerances, is provided to prevent rattling. This fastening device features a bolt, which is mounted in a fastening fastened to the seat and rests tightly against one of the rails under the force of a spring.
Finally, DE-OS11680269 describes a device for fastening a seat onto a floor. Here, we are dealing with a slip-in guide with interlocking rails, whereby it has one pair of rails whose rails interlock perpendicularly to the rails"" longitudinal axis without any significant play, whereas the rails of all the remaining pairs can slide relative to each other transversely to the seat. Work tolerances are thereby supposed to be compensated by sliding the rails of the latter pairs transverse to the seat.
It is the objective of the present invention, to create a seat guide of the generic type, that guarantees steady operation without trouble during longitudinal adjustment, without jamming in particular, using inexpensive resources.
In accordance with the teachings of the present invention, a seat guide for positional adjustment of a vehicle seat along an axis of displacement is provided. The seat guide includes a first guide rail positioned parallel to the axis of displacement and a second guide rail spaced apart from the first guide rail along a lateral axis and positioned parallel to the axis of displacement. At least one support roller is operably associated with and moveable relative to the first guide rail and the second guide rail. Additionally, at least one lateral guide device is operably associated with and moveable relative to the first guide rail and the second guide rail with at least a portion of the at least one lateral guide device being moveable about an axis substantially perpendicular to the axis of displacement.
This is achieved in accordance with the invention, that in combination with the support rollers known by themselves, special lateral guide devices, cooperating with the guide rails by elastic rolling friction, are provided for lateral support in the direction of a lateral axis running essentially perpendicular to both the axis of displacement and the guide rails, especially guide rollers whose rolling and relative motion cooperates with the guide rails.
When the car seat is adjusted, the embodiment in accordance with the invention will only produce elastic rolling friction, because it deals with pure guide rollers. If the seat should tilt while its longitudinal position is being adjusted, i.e. tilting around its vertical axis, then at least one part of the lateral guide rollers will become arranged on at least one assigned guide surface of the respective guide rail, so that only very small rolling friction will also occur here, whereby catching or even wedging will be safely eliminated during seat adjustment.
One favorable embodiment of the invention allocates at least two guide rollers, separated in the direction of the axis of displacement, to each of the two guide rails. The clearance of each lateral pair""s two guide rollers should be chosen as large as possible, depending on structural factors. The seat guide in accordance with the invention is thereby particularly suitable for wide bench seats, two-person or three-person bench seats for example. If there is any tipping, two guide rollers diagonally opposite each other will both become arranged on the two guide rails, so that jamming will be completely eliminated.
The seat guide in accordance with the invention can be realized with inexpensive resources, because conventional rolling bearings can be used as rollers.
The compensation of lateral dimensional tolerances can also be achieved without problem, because the rollers can be guided in the guide rails with a known permissible lateral play. Two minor lateral movements of the seat are indeed possible here, but these are favorably bounded by the guide rollers of the lateral guide devices, without a significant amount of extra friction occurring during adjustment.
In another favorable embodiment of the invention, compensating means are provided for relative support of the seat in a direction opposite to that in which the support rollers bear the load. In principle, slip-in guides can be used here, but it is particularly preferable if the compensating means on the side of each guide rail feature at least one compensating roller for resting and rolling on a supporting surface on the guide rails that is opposite the direction of load-bearing. It is the objective of these compensating means, to prevent rocking motion of the seat around its lateral axis or to minimize such motion, respectively.
To prevent any noise, especially rattling while driving, it is preferable to provide each provided roller with a raceway composed of an elastic material. This could possibly be dispensed with only for the support rollers, because these always abut the guide rails because of their weight.
If there are large stresses on the car seat, the provided rollers alone may not be capable of directing the working forces out of the seat, through the guide rails, and into the vehicle floor. To ensure that the car seat is securely supported in this case, a preferred embodiment of the invention provides special features to directly support the seat on stationary body components. These features can be built by providing the seat guide""s components with web-like impact profile cutouts that interlock with playing distance, whereby these cutouts arrange against each other in the event large stresses occur.